The present invention relates to steam traps and in particular to a float-type steam trap having an improved temperature responsive control arrangement.
Float-type steam traps are well known and are effective in applications where the trap is in constant use. In these traps a float controls a flow of water from a float chamber through a valve seat in the bottom of the chamber as the liquid level within the chamber rises and falls. When a system using a float trap is in intermittent service, it has been found advantageous to purge gasses accumulated while the system was out of service through an additional valve in the top of the trap. The gas purging valve is open during start up of the system and is usually controlled by a thermostatic element.
The thermostatic element allows flow through the upper valve during start up of the system to purge air and other gasses from the lines. When steam is first introduced to the system, it pushes the cold, collected gasses in front of it. When these gasses reach the steam trap, they flow through the upper valve and are vented into the atmosphere or elsewhere. Once steam reaches the trap, the thermostatic element closes the upper valve. It is important that the thermostatic element operate quickly and effectively to seal the valve so that the valuable steam is not wasted.